When obtaining sulfuric acid from pyrite concentrates, a significant amount of waste is generated in the form of pyrite cinders that require disposal. The methods used in processing this raw material are, as a rule, the pyrometallurgical processes of chlorination and chloride sublimation, the disadvantages of which include increased energy consumption and a lack of complexity in the extraction of valuable components. Hydrometallurgical processes are in less demand due to their multi-stage nature and complexity of execution. The method of chemical activation developed at the JSC “Institute of Metallurgy and Ore Beneficiation” makes it possible to isolate iron and non-ferrous metals into separate, middling products and to concentrate noble metals in the cake at the first stage. Physical and chemical studies of the cake found that its basis comprises iron compounds. The silver in the cake is associated with pyrite, while the gold is associated with hematite; it is also possible to find gold in the form of AuCl₃. The content of gold in the cake is 1.5 g/t, and the silver content is 17.7 g/t. Based on physical and chemical studies and data from the literature, various versions of the hydrochlorination method are proposed to open the cake.

Hydrometallurgical processing of uranium-containing raw materials generates a significant amount of liquid industry-related waste, namely waste solutions that require disposal. Sorption is known as one of the most effective methods for purifying liquid matters contaminated with radionuclides. Various modification options are being developed for the purpose of using natural sorbents and increasing their sorption capacity. The authors proposed the methods for modifying natural aluminosilicate and coal-mineral raw materials. Zeolite found at the Kusmurun deposit and shungite from the Koksu deposit were selected for the research. The methods are based on obtaining solid-phase extractants. It was proposed to modify natural sorbents with a mixture of tributyl phosphate and di2-ethylhexyl phosphoric acid in kerosene, as well as a mixture of phosphoric acid and polyacrylamide. It was demonstrated that the first method is preferable for zeolite, and the second one for shungite. The research addressed the sorption properties of modified sorbents in static and dynamic modes. Uranium sorption isotherms were plotted. The maximum sorption capacity and the Langmuir constant were calculated. The research allowed synthesizing an organopolymer based on shungite, glycidyl methacrylate, orthophosphoric, and hydroxyethyl diphosphoric acids. Its sorption properties were studied under dynamic conditions. Its sorption capacity was assessed in comparison with modified natural sorbents.

Recently, more and more attention is paid to the ecological safety of the republic due to the increased threat of environmental pollution by radionuclides, particularly by uranium, while the processing of uranium-containing raw materials generates a significant amount of liquid industrial waste. The main waste disposal method is a sorption, which requires the use of inexpensive sorbents. Such sorbents can be obtained on the basis of domestic natural raw materials. The significant disadvantages of natural sorbents are a low sorption capacity, which can be increased by developing effective and relatively cheap methods for their modification. The absence of the methods of modification is a limiting factor for the widespread using of natural sorbents for environmental purposes. Variants of modification of natural aluminosilicate and coal-mineral raw materials of Kazakhstan by physical and chemical methods are considered. The chemical methods include the modification with a mixture of tributylphostat and di-2-ethylhexylphosphoric acid in kerosene to obtain "solid-phase extractants", a mixture of phosphoric acid and polyacrylamide, and the synthesis of organominerals. The possibility of using technogenic raw materials as a modifying reagent has been studied. Zeolite of the previously unexplored Kosmurun deposit and shungite of the Koksu deposit were selected for research, and slags of phosphorus production were selected as a technogenic raw materials. Their physical and chemical properties have been studied.

Deep reduction of copper smelting slags is a promising route to recover entrained non-ferrous metals and to generate slags suitable for further processing. This work investigates the depletion of fayalite–magnetite slags formed during autogenous smelting of copper concentrates in conditions simulating the oxidation and reduction zones of a two-zone Vanyukov furnace. Laboratory charges of 100 g, containing 14.63–16.82 wt.% Cu, 25.6–27.6 wt.% Fe, 30 wt.% S and 15 wt.% SiO₂, were smelted at 1350 °C with controlled oxygen injection to produce slags containing 0.93–1.54 wt.% Cu, 30.05–32.30 wt.% SiO₂ and 7.8–9.8 wt.% Fe₃O₄. Subsequent reduction at 1300 °C was carried out with activated carbon in a fivefold stoichiometric excess relative to magnetite, at an oxygen-containing blast flow rate of 5 L/h and a 1 h holding time. Chemical analysis shows that Fe₃O₄ in slag decreases from 7.8–7.95 wt.% to 2.5–2.6 wt.%, while copper content drops from 0.93–1.033 wt.% to 0.43–0.50 wt.% under oxygen partial pressures of 10⁻¹²–10⁻¹¹ atm. X-ray diffraction and electron microscopic studies reveal a transition from fayalite–magnetite slags with dispersed metallic copper and sulfides to fayalite-dominated matrices containing ferruginous sphalerite, copper minerals of the bornite–chalcopyrite type, iron oxides and glassy phases. Simultaneous thermal analysis demonstrates that all major endothermic and exothermic events are completed by 1300 °C, supporting this as an optimal temperature for deep slag depletion. The results define an operating window—slag composition, temperature, reductant dosage and pO₂—under which copper losses to slag can be reduced to about 0.5 wt.% in industrially relevant fayalite slags.